Abrasive breaking method



Jan. 27, 1970 H. F. e. UELTZ ETAL 3,491,929

United States Patent O 3,491,929 ABRASIVE BREAKING METHOD Herbert F. G. Ueltz, Youngstown, and Alfred G. Rzucidlo, Niagara Falls, N.Y., assignors, by mesne assignments, to U.S. Industries, Inc., New York, N.Y., a corporation of Delaware Filed Jan. 15, 1968, Ser. No. 697,904 Int. Cl. B26f 3/00; B6Sh 35/00, 35/10 U.S. Cl. 225-4 2 Claims ABSTRACT OF THE DISCLOSURE A breaking device for a sheet of abrasive material comprising -a pair of rolls, one of steel and the other of steel encased With a resilient jacket so as to apply pres sure through an arcuate surface on one side of the abrasive sheet forcing it into the resilient cover or jacket on the other abrasive roll generally conforming it to the shape of the hard surface roll with the pressure such as to cause the sheet to break into cuboidal pieces.

Reference to related applications In a co-pending application entitled Abrasive and Method of Making Ser. No. 697,905, there appears a step in Which dried plate-like ceramic cakes are broken mechanically to give generally cubical or cuboidal shape grains.

Background of the invention The cakes resulting from the prior processing as described in the co-pending application above may be broken into fragments by a number of methods such las roll crushing, rod milling and impact milling. It has been found that such methods, using usual equipment currently available on the market breaks the cakes into fragments having a generally irregular, angular, or elongated shape. The desired shape is approxmately cubical or equiaxial.

Summary of the invention We have found that dried ceramic plates or cakes may be broken into cuboidal grains by passing the plates through rollers having differing degrees of flexibility or resilience. We prefer that one roller be made of a hard material like steel, while the other roller has a resilient surface such as is obtained by encasing a metal roller in a rubber jacket.

Brief description of the drawings FIG. 1 is a perspective view of the breaking apparatus; and

FIG. 2 is a sectional view on a larger Scale 'of the two rollers With a sheet of abrasive material being broken between them.

Description of the preferred embodiment In the drawings 10 designates a suitable framework or stand for supporting the two rolls and the motor for driving them, there being a steel roll 11 With a hard surface supported in bearings 12 on shaft 13 which shaft has a pulley 14 on one end driven by a motor 15 through shaft 16 and pulley 17 thereon With belt 18 about the pulleys 14 and 17. Steel is chosen because of its hard surface, although any suitable hard surface roll might be provided. suitable pillow block bearings 20 are Secured by bolts 21 in slots in the frame 10 and carry a shaft 22 upon Which there is mounted a resiliently covered roll 23. This roll has a steel center 24 and an encasing rubber jacket 25 of a thickness which will provide the desired resiliency for this operation. We have found that each of the steel "lce rollers 11 and 24 may be four inches in diameter with the encasing rubber jacket 25 being of an inch in diameter and formed of foam rubber. The bearings 20 may be adjusted by screws 26 through threaded block 27 to move roll 23 toward roll 11.

The abrasive sheet which is formed as set forth more fully in the above-mentioned application is designated '30 (FIG. 2) and is of a thickness substantially one dimension of the cuboidal size of grain Which is to be produced. This sheet is fed between the rolls 11 and 23 and the surface of the sheet With Which the steel roller 11 contact is caused to be given a concave shape such as shown in the drawing by reason of its being forced into the resilient cover 25 on the roll 23. The breaking of the sheet provides grains such as 31 the size of which depends to a larger extent upon the pressure Which is provided on the sheet by the rolls, the adjustment being by moving the pillow blocks 20 through the screw devices 26 to acquire the pressure desired. A cross bending force occurs as illustrated in the sheet of abrasive material and simultaneously the resilient surface is deformed outwardly from the point of pressure which places the plate being broken under tension. The combination of the cross breaking force and the tension has been found to cause the abrasive plate to fracture into pieces of generally cuboidal shape. The shape depends upon the selection of the plates thickness and the initial pressure between the rolls. If the pressure between the rolls is too great, the plates will be pulverized, while if the pressure is not suflicient, the plates will not be broken to a degree that will give approximately equiaxial or cuboidal shapes. However, a pressure may be chosen With this apparatus through the adjusting screws so that the pressure between the rolls may be set which Will produce a breaking of the sheet so that the length of the breaking particles will be substantially the same as the thickness of the particles, and it is found that the breaking When this occurs also causes a breaking width- Wise of the sheet as -well as lengthwise of the sheet so that substantially cubes such as shown at 31 are provided. It Will of course be apparent that diferent thickness of sheets Will take different adjustments of the position of the roll 23 to aiord diierent pressures, but pressures may be pro- Vided easily by adjusting so that the cuboidal shapes are provided.

We claim:

1. The method of *breaking sheets of abrasive material of generally uniform surface and undiminished in thickness comprising forcing the sheet by a non-compressible arcuate surface against an arcuate resilient surface With a degree of pressure to break the sheet into pieces substantially the dimension of the thickness of the sheet.

2. The method of breaking sheets of abrasive material of generally uniform surface and undiminished in thickness comprising forcing the sheet by a non-compressible arcuate surface against an arcuate resilient surface With a degree of pressure to break the sheet into pieces substantially the length and width of the thickness of the sheet.

References Cited UNITED STATES PATENTS 409,186 8/1889 Friend 241 102 X '552,748 1/1896 Crippen 241-102 X 672,833 '4/1901 Scheirer 241-102 X 3,396,452 8/1968 Sato et al. 225-98 X FOREIGN PATENTS 27,943 7/1884 Germany.

J AMES -M. MEISTER, Primary Examiner U.S. Cl. X.R. 225-98 

